This present invention relates to an improvement to a fuel cap, and more particularly to a fuel cap adapted to cleanse incoming ambient air and, upon re-fueling, protect the environment by cleansing escaping vapors from pollutants and other contaminants. In the past, most fuel caps for all fuel-powered objects (such as cars, trucks, motorcycle, motor boats, airplanes, and power lawn and gardening equipment, for example) merely were applied to the neck emanating from the fuel tank for the sole purpose of preventing loss of fuel during operation.
The Air Pollution Control Board (APCD) states that non-attainment areas for Ozone are serious problems all over the country. A non-attainment area is an area that is in noncompliance with the federal and/or state air quality standards. Currently, the most disconcerting component of smog is Ozone. Ozone is a strong irritant that can cause restriction of the airway, forcing the respiratory system to work harder in order to provide oxygen.
Chronic exposure reduces lung capacity, lowers stamina, and leaves people vulnerable to long-term respiratory problems. Smog is especially harmful for children whose lungs are still developing, senior citizens whose immune systems are weakening, and those who suffer from asthma and chronic lung disease. Gasoline vapor expelled during the fueling process is a major contributor to Ozone.
When cars are driven, fuel is delivered to the engine via a fuel pump. In most modern vehicles, fuel injection for example, high fuel pressures are necessary for the vehicles to operate properly. It is not uncommon for the fuel pressure regulator, in a modern vehicle, to operate at fuel pressures exceeding 35 psi. These pressures are created by high fuel pump flows delivering gasoline to the engine from the fuel tank. Typical modern fuel pump flows can exceed 30 gal per hour and even higher on performance cars. Since the fuel pump is providing more fuel to the engine than the engine can use (in order to maintain the required high pressures), the unused fuel is then re-routed back to the fuel tank.
This cycle continues to take place over and over and the rate of this cycle increases as the fuel level in the tank continues to decreases. For example, a typical car may be operating with about 5 gallons of fuel in the tank and the car has a fuel pump capable of pumping 30 gallons per hour to the engine. In this situation, the fuel in the tank is being pumped to the engine and back to the tank at least 6 times every hour.
Consequently, the same fuel is being cycled from the tank to the engine, and back to the tank over and over again. As previously mentioned, this high flow cycle is required to keep the fuel delivery systems operating at the proper fuel flows and pressures.
Typical engine temperatures, at the intake manifold (where the fuel is typically delivered) can range from about (160-240 degrees). Therefore, each time the fuel passes though the engine and is cycled back to the tank, the fuel is heated. This heated fuel, when it returns to the tank, raises the temperature of the gasoline in the tank. Once the gasoline in the tank has been heated, this then raises the temperature of the air/gas vapor (hydrocarbon vapor) in the tank. The higher temperature in the tank causes the vapors to expand and this expansion causes the internal pressures inside the fuel tank to rise.
This increased pressure causes the vapor release of Volatile Organic Compounds (VOCs) or “blow by” drivers experience when they remove the gasoline cap prior to refueling. Simply stated, during operation, the fuel in the tank travels from the fuel tank to the engine, then the unused fuel flows back to the tank. This cycle is continued and causes the fuel in the tank to be continuously heated. This heated fuel causes the fuel in the tank and its vapors to expand which raises the tank pressure or causes a positive pressure in the tank. Although this condition happens continuously during operation, the condition can be exasperated during hot summer days. When refueling is desired and the fuel cap is removed, the built-up pressure surges outward expelling vapors containing various pollutants and contaminants.
Various Air Resource Boards (ARB) report that motor vehicles contribute the biggest source of air pollution. Conventional gasoline-powered and diesel vehicles contribute more than 60 percent of the smog-forming pollutants. The ARB further state that Evaporative Emissions (emissions from evaporating gasoline, which occurs during vehicle fueling), can account for two-thirds of the hydrocarbon emissions released to the air from gasoline-fueled vehicles. Gasoline vapor is a volatile organic compound (VOC). Per the department of Washington State Air Toxic Sources, up to 9 grams per vapor gallon of concentrated VOC vapors are released when the gasoline cap is removed prior to refueling. Currently, in the state of California alone, there are approximately 27 million registered vehicles and nationally, according to the US Department of Transportation, there are approximately 225 million registered vehicles. Without the gas cap described herein, these vehicles, when their caps are removed for fueling, will vent, within the state of California, approximately 14,000 tons of raw pressurized VOCs and nationally approximately 109,000 tons of VOCs. Although some variations will persist between various design constraints, properly designed caps, as described herein, will cleanse approximately 95-99.7% of the pressurized VOC vapor contaminants normally released during cap removal as reflected in the numbers above. These numbers however do not include the additional vapor releases caused by boats, aircraft, off-road vehicles, lawnmowers, generators and other equipment as the cap described herein will also remove these contaminates.
Most gas caps for vehicles also have a venting capability which allows ambient air to pass through the cap and into the gas tank as the gas level drops and the air void above the gas increases. The ambient air entering the gas tank generally contains varying amounts of ambient moisture and other pollutants and contaminants. Such pollutants and contaminants (including moisture) can disrupt the efficiency of the motor and cause long-term damage to the motor.
The amount of moisture entering the gas tank, naturally, is much higher in more humid climates. The moisture ultimately condenses in the gas tank and mixes with the gas thereby decreasing the efficiency and performance of the vehicle and, over time, causing damage to the vehicle.
Over time, fuel caps have been devised to permit a gradual release of vapors into the atmosphere while the motorized object is in operation and to permit release of built-up pressure before removal of the fuel cap prior to refueling. Some have even incorporated filtering into the venting process during normal operation or to regulate or to relieve the maximum fuel pressures in a fuel tank to a predetermined limit. None, however, has incorporated a cleansing of ambient air into the fuel tank during operation nor incorporated a cleansing by absorption of pollutants and contaminants during cap removal as pressurized vapors are cleansed while they are expelled into the atmosphere.
The fuel cap described herein rises above all prior art fuel caps in that it accomplishes a bi-lateral cleansing by absorption of ambient air entering the fuel tank and cleansing by absorption of pollutants and contaminants from vapors being expelled during cap removal. The cap will force the user to clean any pressurized tank vapors through the cap during the cap removal process as the cap cannot be removed without first venting the vapors through the cap. This process will also greatly enhance personal safety during refueling since the cleansed vapors being expelled through the cap will now be virtually inflammable and provide the user with an added level of fire safety. And since the pressures in the tank will be relieved prior to cap removal, the chances of accidental fuel expulsion due to high tank pressures are greatly reduced.
Moreover, the fuel cap described herein also incorporates a sensor which detects the level of pollutants and contaminants absorbed thereby alerting the user when the absorption media has absorbed pollutants and contaminants to capacity at which time, the spent fuel cap and/or absorption media should be replaced.
Some of the pertinent objects of the presently described fuel cap include, but are not limited to:
a. Vapor cleansing by absorption of contaminants and pollutants in ambient air as ambient air enters the fuel tank during operation of the motorized object;
b. Vapor cleansing by absorption of contaminants and pollutants in fuel vapors in the fuel tank as they are expelled through the cap when the fuel cap is removed for refueling or inspection;
c. Providing a cleansing media by absorption suited to absorb contaminants and pollutants from ambient air and from expelled fuel vapors; and
d. Incorporating a means to detect when the cleansing media has reached capacity of absorbed contaminants and pollutants.
The foregoing has outlined some of the more pertinent objects of the presently described fuel cap. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the intended presently described fuel cap. Many other beneficial results can be attained by applying the disclosed fuel cap in a different manner or by modifying the presently described fuel cap within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the presently described fuel cap may be had by referring to the summary of it and the detailed description of the preferred embodiment in addition to the scope of the presently described fuel cap defined by the claims taken in conjunction with the accompanying drawings.